/*
 * contrib/btree_gist/btree_numeric.c
 */
#include "postgres.h"

#include "btree_gist.h"

#include <math.h>
#include <float.h>

#include "btree_utils_var.h"
#include "utils/builtins.h"
#include "utils/numeric.h"
#include "utils/rel.h"

/*
** Bytea ops
*/
PG_FUNCTION_INFO_V1(gbt_numeric_compress);
PG_FUNCTION_INFO_V1(gbt_numeric_union);
PG_FUNCTION_INFO_V1(gbt_numeric_picksplit);
PG_FUNCTION_INFO_V1(gbt_numeric_consistent);
PG_FUNCTION_INFO_V1(gbt_numeric_penalty);
PG_FUNCTION_INFO_V1(gbt_numeric_same);


/* define for comparison */

static bool
gbt_numeric_gt(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
    return DatumGetBool(DirectFunctionCall2(numeric_gt,
                                            PointerGetDatum(a),
                                            PointerGetDatum(b)));
}

static bool
gbt_numeric_ge(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
    return DatumGetBool(DirectFunctionCall2(numeric_ge,
                                            PointerGetDatum(a),
                                            PointerGetDatum(b)));
}

static bool
gbt_numeric_eq(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
    return DatumGetBool(DirectFunctionCall2(numeric_eq,
                                            PointerGetDatum(a),
                                            PointerGetDatum(b)));
}

static bool
gbt_numeric_le(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
    return DatumGetBool(DirectFunctionCall2(numeric_le,
                                            PointerGetDatum(a),
                                            PointerGetDatum(b)));
}

static bool
gbt_numeric_lt(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
    return DatumGetBool(DirectFunctionCall2(numeric_lt,
                                            PointerGetDatum(a),
                                            PointerGetDatum(b)));
}

static int32
gbt_numeric_cmp(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
    return DatumGetInt32(DirectFunctionCall2(numeric_cmp,
                                             PointerGetDatum(a),
                                             PointerGetDatum(b)));
}


static const gbtree_vinfo tinfo =
{
    gbt_t_numeric,
    0,
    FALSE,
    gbt_numeric_gt,
    gbt_numeric_ge,
    gbt_numeric_eq,
    gbt_numeric_le,
    gbt_numeric_lt,
    gbt_numeric_cmp,
    NULL
};


/**************************************************
 * Text ops
 **************************************************/


Datum
gbt_numeric_compress(PG_FUNCTION_ARGS)
{
    GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);

    PG_RETURN_POINTER(gbt_var_compress(entry, &tinfo));
}



Datum
gbt_numeric_consistent(PG_FUNCTION_ARGS)
{
    GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
    void       *query = (void *) DatumGetNumeric(PG_GETARG_DATUM(1));
    StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);

    /* Oid        subtype = PG_GETARG_OID(3); */
    bool       *recheck = (bool *) PG_GETARG_POINTER(4);
    bool        retval;
    GBT_VARKEY *key = (GBT_VARKEY *) DatumGetPointer(entry->key);
    GBT_VARKEY_R r = gbt_var_key_readable(key);

    /* All cases served by this function are exact */
    *recheck = false;

    retval = gbt_var_consistent(&r, query, strategy, PG_GET_COLLATION(),
                                GIST_LEAF(entry), &tinfo, fcinfo->flinfo);
    PG_RETURN_BOOL(retval);
}



Datum
gbt_numeric_union(PG_FUNCTION_ARGS)
{
    GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
    int32       *size = (int *) PG_GETARG_POINTER(1);

    PG_RETURN_POINTER(gbt_var_union(entryvec, size, PG_GET_COLLATION(),
                                    &tinfo, fcinfo->flinfo));
}


Datum
gbt_numeric_same(PG_FUNCTION_ARGS)
{
    Datum        d1 = PG_GETARG_DATUM(0);
    Datum        d2 = PG_GETARG_DATUM(1);
    bool       *result = (bool *) PG_GETARG_POINTER(2);

    *result = gbt_var_same(d1, d2, PG_GET_COLLATION(), &tinfo, fcinfo->flinfo);
    PG_RETURN_POINTER(result);
}


Datum
gbt_numeric_penalty(PG_FUNCTION_ARGS)
{
    GISTENTRY  *o = (GISTENTRY *) PG_GETARG_POINTER(0);
    GISTENTRY  *n = (GISTENTRY *) PG_GETARG_POINTER(1);
    float       *result = (float *) PG_GETARG_POINTER(2);

    Numeric        us,
                os,
                ds;

    GBT_VARKEY *org = (GBT_VARKEY *) DatumGetPointer(o->key);
    GBT_VARKEY *newe = (GBT_VARKEY *) DatumGetPointer(n->key);
    Datum        uni;
    GBT_VARKEY_R rk,
                ok,
                uk;

    rk = gbt_var_key_readable(org);
    uni = PointerGetDatum(gbt_var_key_copy(&rk));
    gbt_var_bin_union(&uni, newe, PG_GET_COLLATION(), &tinfo, fcinfo->flinfo);
    ok = gbt_var_key_readable(org);
    uk = gbt_var_key_readable((GBT_VARKEY *) DatumGetPointer(uni));

    us = DatumGetNumeric(DirectFunctionCall2(
                                             numeric_sub,
                                             PointerGetDatum(uk.upper),
                                             PointerGetDatum(uk.lower)
                                             ));

    os = DatumGetNumeric(DirectFunctionCall2(
                                             numeric_sub,
                                             PointerGetDatum(ok.upper),
                                             PointerGetDatum(ok.lower)
                                             ));

    ds = DatumGetNumeric(DirectFunctionCall2(
                                             numeric_sub,
                                             NumericGetDatum(us),
                                             NumericGetDatum(os)
                                             ));

    if (numeric_is_nan(us))
    {
        if (numeric_is_nan(os))
            *result = 0.0;
        else
            *result = 1.0;
    }
    else
    {
        Numeric        nul = DatumGetNumeric(DirectFunctionCall1(int4_numeric, Int32GetDatum(0)));

        *result = 0.0;

        if (DirectFunctionCall2(numeric_gt, NumericGetDatum(ds), NumericGetDatum(nul)))
        {
            *result += FLT_MIN;
            os = DatumGetNumeric(DirectFunctionCall2(
                                                     numeric_div,
                                                     NumericGetDatum(ds),
                                                     NumericGetDatum(us)
                                                     ));
            *result += (float4) DatumGetFloat8(DirectFunctionCall1(numeric_float8_no_overflow, NumericGetDatum(os)));
        }
    }

    if (*result > 0)
        *result *= (FLT_MAX / (((GISTENTRY *) PG_GETARG_POINTER(0))->rel->rd_att->natts + 1));

    PG_RETURN_POINTER(result);
}



Datum
gbt_numeric_picksplit(PG_FUNCTION_ARGS)
{
    GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
    GIST_SPLITVEC *v = (GIST_SPLITVEC *) PG_GETARG_POINTER(1);

    gbt_var_picksplit(entryvec, v, PG_GET_COLLATION(),
                      &tinfo, fcinfo->flinfo);
    PG_RETURN_POINTER(v);
}
